This invention relates to a guard for protecting a door lock, which locks a swingable door to a door frame and more particularly to a door lock guard which will impede the passage of a burglary tool between the door guard and the adjacent portion of the door and door frame.
Many door lock guards for latch bolts have been provided heretofore for attempting to inhibit the unauthorized opening of a locked door via a flat burglar's blade which is slipped under or past a loosened or removed door stop. Once the prior art door guard is installed, the guard itself presents a smooth surface which will permit a flat bladed instrument to easily slide thereon without any substantial resistance.
Accordingly, an object of the present invention is to provide an effective impediment to the passage of a flat burglary card along the surface of a guard device by the provision of a guard device which has a jagged surface that resists such sliding movement.
Although a door tightly abuts a vertical stop rail on the door jamb when the door is closed to inhibit a jimmy forcing the door apart from its jamb sufficiently to allow the latch bolt to be forced over the strike plate, doors sometimes warp and do not close tightly against the rail stop. A burglar can insert a thin flat card between the door and the jamb at the warped portion of the door and then move the flexible jimmy card vertically to a position overlying the latching bolt to force the latching bolt to a retracted position.
Accordingly, it is another object of the present invention to provide a door guard which will deter such unauthorized, surreptitious access and tampering.
Accordingly, it is another object of the present invention to provide a lock guard which is L-shaped in cross section and has a dentated surface providing a plurality of teeth defining an uneven surface that impedes the passage of a flat burglary plate or card in the vertical and horizontal directions.
Other objects and advantages of the present invention will become apparent to those of ordinary skill in the art as the description thereof proceeds.